"It's not all covered... we have co-pays," said Kim. "Right now, I've been fighting with insurance since August to get him occupational therapy."

The cost of providing care for a person with autism in the U.S. is an estimated $1.4 million over their lifetime, according to a study funded by advocacy group Autism Speaks. For those with autism who are impacted with intellectual disabilities (with an IQ of 70 or less) -- nearly half of the autistic population -- the cost jumps to $2.3 million.

That's in addition to the standard costs associated with raising a child, including food, education and housing.

"The burden on families affected by autism is enormous," said Mark Roithmayr, president of Autism Speaks. "Immediately parents are faced with bills that are not being covered so they turn to second mortgages or home equity lines of credit, then they turn to credit cards and other family members and at that point they are out of options."

Kate Movius has spent nearly $200,000 in the eight years since her 11-year old son Aidan was first diagnosed with autism.

In 2005, she took out a $30,000 home equity line of credit so she could afford alternative treatments like vitamin therapy, on top of the occupational therapy, speech therapy and behavioral therapy she was already paying for. "You are so desperate as a parent and you just think I'm going to do everything I can," she said.

Since then, Movius says she has reined in some of the expenses. Today, Movius estimates her family spends $9,000 to $10,000 a year on un-reimbursed medical costs, but it's hardly enough.

While medical costs, such as outpatient care, home care and medicine, contribute significantly to the total expense, non-medical expenses, including special education, therapy, daycare and care and housing for adults who age out of school and can no longer live at home with their parents, account for the largest proportion of autism costs, according to the study.

Altogether, the total annual cost to the U.S. is estimated to be $137 billion, according to Autism Speaks, as more children than ever before are being diagnosed with autism spectrum disorders, or ASDs.

About one in 88 children in the United States are now affected, according to a recent tally by the Centers for Disease Control and Prevention, that's up 23% from the CDC's last report in 2009.

Adding to the severe financial strain, families with autistic children also earn 28% less overall compared to families whose children do not have health limitations, according to a recent report in the journal Pediatrics. For mothers, the disparity is even starker, with earnings that are 56% less than those of mothers of children with no physical or mental limitations.